Abstract Ettringite is a key compound of cementitious materials, formed during hydration that influences the rheological behavior of the cement paste. Despite its importance, ettringite formation has been poorly studied. In this work, nucleation and growth processes of ettringite were separately investigated. Ettringite nucleation was described using the Classical Nucleation Theory and an interfacial crystal-solution energy was determined. After the initial primary homogeneous nucleation, when the surface of already formed crystals was still low, the precipitation rate was shown to depend almost exclusively on the solution supersaturation. When the surface of crystals in suspension was getting bigger, a secondary nucleation responsible for an increase of ettringite needle diameter was observed. The precipitation rate became surface dependent and increased significantly. Results of this work show that nucleation of ettringite is easy as it requires few energy and that after primary nucleation precipitation occurs rapidly via secondary nucleation and growth.

中文翻译：

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钙矾石在稀释条件下的成核和生长过程研究

摘要 钙矾石是胶凝材料的关键化合物，在水化过程中形成，影响水泥浆的流变行为。尽管钙矾石很重要，但对钙矾石的形成研究甚少。在这项工作中，钙矾石的成核和生长过程分别进行了研究。钙矾石成核是使用经典成核理论描述的，并且确定了界面晶体-溶液能量。在最初的初级均匀成核之后，当已经形成的晶体的表面仍然很低时，沉淀速率几乎完全取决于溶液的过饱和度。当悬浮晶体的表面变大时，观察到导致钙矾石针直径增加的二次成核。降水率变得依赖于表面并显着增加。这项工作的结果表明钙矾石的成核很容易，因为它需要很少的能量，并且在初级成核后通过次级成核和生长迅速发生沉淀。